The Significance of Silica and Other Additives in Geothermal Well Cementing

Total Page:16

File Type:pdf, Size:1020Kb

The Significance of Silica and Other Additives in Geothermal Well Cementing Orkustofnun, Grensasvegur 9, Reports 2017 IS-108 Reykjavik, Iceland Number 15 THE SIGNIFICANCE OF SILICA AND OTHER ADDITIVES IN GEOTHERMAL WELL CEMENTING Philip Cheruiyot Kemoi Kenya Electricity Generating Company, Ltd. – KenGen P.O. Box 785 – 20117 Naivasha KENYA [email protected] ABSTRACT Geothermal drilling is a capital intensive venture that needs extensive resources to explore and develop to production phase. The well drilling, for instance, involves geoscientific exploration, drilling and casing using cement slurry. The reliability of the power plant will depend on the lifespan of the production wells in the geothermal field. There are many factors that make a well be non-productive, such as poor well casing among others. In high temperature geothermal fields, which are rich with harmful geothermal fluids, there is a need to design and formulate cement slurry that can withstand these environments. Portland cement is stabilised by adding a silica component to achieve good compressive strength development and reduction of permeability in the cement. Pozzolonic Portland cement can be a viable option too. In Olkaria, Kenya, 20% silica flour by weight of cement is used to prevent strength degradation by the CO2 rich environment that causes gas channelling having an adverse impact on cement bond integrity, hence accelerating strength retrogression. Most wells are highly permeable and therefore one of the greatest challenges in cementing is due to circulation losses. Mica flakes are currently used to prevent or minimize losses. New loss of circulation materials such as Cementing Lost Circulation Fibers (CLCF) could be a viable option. The new fluid loss control (FLC) agent ADVA Cast 530 gives improved rheological properties. Other possible alternatives to the challenges of lost circulation are to reduce the density of the slurry by using foam cement or to introduce new additives such as perlite, microspheres and other low density pozzolanic materials. To fully analyse the strength retrogression of well cements in Kenya, that are exposed to high temperatures over their lifetime, tests of cement slurries at the laboratory should ideally be simulated at close to actual well temperatures (bottom hole circulating temperature (BHCT) and bottom hole static temperature (BHST)) over a few months, since this would give a better indication of the strength retrogression. Current research in the geothermal sector seem to lack testing at high enough temperatures over a sufficiently long period. 221 Kemoi 222 Report 15 1. INTRODUCTION Geothermal well cementing is one of the most critical operations of anchoring casings in the well. This is done using cement and cement additives mixed with water in the designed formulation. The objective of any casing cementing program is to ensure that the total length of the annulus (either casing to casing annulus, or casing to open hole annulus) is completely filled with sound cement that can withstand long term exposure to geothermal fluids and temperatures. Geothermal wells require a well designed slurry to give sufficient strength and to provide a seal between the formations during its productive life. Designing a cement slurry for a geothermal well is a complex task which considers a careful choice of cement, retarders, fluid loss additives, dispersants, silica flour, and extenders. The right ratio of additives to blend in the cement should be designed correctly before being used to case the well, considering properties such as good rheological/flow to be able to pump it. It must not set before it has been pumped to the desired location and it should have enough compressive strength with low permeability when it sets. In the design phase, an increase of temperature will decrease the plastic viscosity and yield viscosity. A good laboratory slurry test should be done to evaluate the ratios that are good to counter the strength retrogression. The silica flour additive acts as an anti-retrogression agent at high temperatures. When carbon dioxide (CO2) is present such as in Olkaria, 15-20% of silica flour by weight of cement (BWOC) is used to make the cement resistant to CO2. In Iceland, the temperatures can be very high but CO2 has not been an issue, and therefore, 40% silica flour (BWOC) can be used. This paper seeks to analyse the importance of using silica flour and other additives when carrying out geothermal well cementing operations in wells located in high temperature geothermal fields. 1.1 Well cementing Well cementing is the process of mixing a cement slurry composed of dry cement, water, and additives and pumping it down through a steel casing to the annular space between the wall of the well and the outside of the casing as shown in Figure 1. It consists of primary cementing and remedial cementing. Primary cementing is the process of placing a cement sheath in the annulus between the casing and the formation, while remedial cementing occurs after primary cementing where the cement is injected into strategic well locations for various purposes, including well repair and abandonment. 1.2 The importance of cementing The dry cement is converted to slurry cement by mixing it with water and cement additives through a well FIGURE 1: Typical cementing process (API 2009) Report 15 223 Kemoi formulated design in the laboratory and it is pumped through the annulus from the surface of the geothermal well to facilitate the sound integrity of the well and improve its life span and performance. The well acts as a high-pressure containment vessel at elevated temperatures which should resist failure by deformation, fatigue, fracturing, and corrosion during its operating life (Agapiou and Charpiot, 2013). The most important functions of a cement sheath between the casing and the formation are: a) To prevent the movement of liquid from one formation to another or from the formation to the surface through the annulus. b) Provision of mechanical support of the casing string with associated wellhead equipment in the well. c) To support the well bore walls (in conjunction with the casing) to prevent the collapse of the formation. d) To prevent blowouts by forming a seal in the annulus. e) Protection of the casing from corrosion. Cementing is also used to condition the well: a) To seal loss of circulation zones. b) To stabilize weak zones (washouts, collapses). c) To plug a well for abandonment or for repair. d) To kick off side tracking in an open hole or past junk. e) To plug a well temporarily before being re-cased. 1.3 Geothermal well slurry design In general, there are five steps in designing a successful cement placement: a) Analysing the well conditions: reviewing objectives for the well before designing placement techniques and cement slurry to meet the needs of the life of the well. Fluid properties, fluid mechanics and chemistry all influence the design used for well. b) Determining slurry composition and performing laboratory tests on the fluids designed in the first step to make sure they meet the requirements. c) Determining the slurry volume to be pumped, using the necessary equipment to blend, mix and pump the slurry into the annulus, establishing backup and contingency procedures. d) Monitoring the cement placement in real time: comparisons should be made with the first step and make adjustments where necessary. e) Post-job evaluation of the result of the cementing operation is a continuous process and should be compared with the design in the first step and adjusted accordingly where necessary. 2. CEMENT PROPERTIES AND ADDITIVES 2.1 Cement Classifications Cement is manufactured by fusing calcium carbonate (limestone) and aluminium silicate (clay) with small iron and with a possible addition of gypsum (calcium sulfate dehydrate). Its major component is tricalcium silicate which reacts with water to form calcium silicate hydrate (CSH). There are several types of cement being manufactured for geothermal well use. Typical cement used for geothermal wells are class A and G. The American Petroleum Institute (API) Spec 10A classifies cement into classes listed below: Kemoi 224 Report 15 1) Class A - Intended for use when special properties are not required and available in ordinary (O) grade. 2) Cass B - Intended for use when conditions require moderate or high sulfate-resistance. It is available in both moderate sulfate-resistant (MSR) and high sulfate-resistant (HSR) grades. 3) Class C - Intended for use when conditions require high early strength. It is available in ordinary (O), MSR and HSR grades. 4) Class D - Intended for use under conditions of moderately high temperatures and pressures. It is available in MSR and HSR grades. 5) Class E - Intended for use under conditions of high temperatures and pressures. It is available in MSR and HSR grades. 6) Class F - Intended for use under conditions of extremely high temperatures and pressures. It is available in MSR and HSR grades. 7) Class G - Intended for use as basic well cement. It is available in MSR and HSR grades. No additives other than calcium sulfate and/or water shall be inter-ground or blended with the clinker during the manufacture of class G well cement. 8) Class H - Intended for use as basic well cement. It is available in MSR grade. No additives other than calcium sulfate and/or water shall be inter-ground or blended with the clinker during manufacture of class H well cement. Cement without any additives that modify setting time or rheological properties is called Neat Cement. This cement should not be used at temperatures > 110°C (230°F) because it loses strength and increases permeability above that temperature. The process is time and temperature dependent. In a test of API Class G (the usual high-temperature oil well cement), it was found that neat cement compressive strength decreased by 77% from 5,050 to 1,150 psi, and permeability increased from 0.012 to 8.3 millidarcy in 60 days at 160°C (320°F) in geothermal brine.
Recommended publications
  • Well Design, Cementing Techniques and Well Work-Over to Land Deep Production Casings in the Menengai Field
    Orkustofnun, Grensasvegur 9, Reports 2014 IS-108 Reykjavik, Iceland Number 17 WELL DESIGN, CEMENTING TECHNIQUES AND WELL WORK-OVER TO LAND DEEP PRODUCTION CASINGS IN THE MENENGAI FIELD Abraham Wamala Khaemba Geothermal Development Company, Ltd. P.O. Box 17700-20100 Nakuru KENYA [email protected] ABSTRACT Drilling has been ongoing at Menengai high temperature field since 2011. The wells are of regular well design with a 20" surface casing set at 60-70 m, 13⅜" anchor casing set at about 400 m depth and 9⅝" production casing set at between 800-1400 m. The intent is to drill the wells to a total depth of 2500-3000 m, with slotted 7" liners run to the bottom. All the casings used are grade K55, with threaded couplings. Data from offset wells drilled earlier have helped design the depth of the production casing in order to avoid cold inflows into the wells. Wells located at the centre of the field, which is at a higher elevation, have production casings set at about 850 m, while the production casings for other wells have been designed to be set deeper, down to 1400 m. With a good number of wells at the Menengai field having the production casing being set at 1400 m, this paper looks at: designing wells with a 9⅝" K55 production casing, slurry design and the most effective method for cementing the casings. Cementing methods that will be discussed include cementing with a cement head and plugs, two stage cementing, cementing with C-Flex RPL from the peak using the inner string method, reverse circulation cementing with an inner string and flap gate valve collar, and foam cementing.
    [Show full text]
  • Geothermal Cementing - the State of the Art
    GEOTHERMAL CEMENTING - THE STATE OF THE ART Stanley H. Shryock and Dwight K. Smith Haliiburton Servfces Unltod States ABSTRACT Much emphasis today is being placed on the drilling and completion of steam wells. Success or failure depends greatly on the cementing pro- cess, which requires not only the selection of competent and durable materials but also the complete understanding of placement techniques Immobile muds, crooked holes, lost circulation, poor centralization, and the inability to move pipe are some of the major areas which con- tribute to good or bad results. This presentation covers a "state of the a of the various tech- niques, materials, and equipnent being used cementing steam wells in the United States and Mexico. Two new teo-hniques which aid in achieving full hole coverage and in sealing lost circulation zones during cementing are highlighted. I I DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency Thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
    [Show full text]
  • Application of Cellulose-Based Polymers in Oil Well Cementing
    Journal of Petroleum Exploration and Production Technology (2020) 10:319–325 https://doi.org/10.1007/s13202-019-00800-8 ORIGINAL PAPER - PRODUCTION ENGINEERING Application of cellulose‑based polymers in oil well cementing Ghulam Abbas1 · Sonny Irawan2 · Khalil Rehman Memon3 · Javed Khan4 Received: 1 November 2018 / Accepted: 4 November 2019 / Published online: 22 November 2019 © The Author(s) 2019 Abstract Cellulose-based polymers have been successfully used in many areas of petroleum engineering especially in enhanced oil recovery drilling fuid, fracturing and cementing. This paper presents the application of cellulose-based polymer in oil well cementing. These polymers work as multifunctional additive in cement slurry that reduce the quantity of additives and lessen the operational cost of cementing operation. The viscosity of cellulose polymers such as hydroxyethyl cellulose (HEC), car- boxymethylcellulose (CMC) and hydroxypropyl methylcellulose (HPMC) has been determined at various temperatures to evaluate the thermal degradation. Moreover, polymers are incorporated in cement slurry to evaluate the properties and afect in cement slurry at 90 °C. The API properties like rheology, free water separation, fuid loss and compressive strength of slur- ries with and without polymer have been determined at 90 °C. The experimental results showed that the viscosity of HPMC polymer was enhanced at 90 °C than other cellulose-based polymers. The comparative and experimental analyses showed that the implementation of cellulose-based polymers improves the API properties of cement slurry at 90 °C. The increased viscosity of these polymers showed high rheology that was adjusted by adding dispersant which optimizes the rheology of slurry. Further, improved API properties, i.e., zero free water separation, none sedimentation, less than 50 ml/30 min fuid loss and high compressive strength, were obtained through HEC, CMC and HPMC polymer.
    [Show full text]
  • The Suitability of Fly Ash Based Geopolymer Cement for Oil Well Cementing Applications: a Review
    VOL. 13, NO. 20, OCTOBER 2018 ISSN 1819-6608 ARPN Journal of Engineering and Applied Sciences ©2006-2018 Asian Research Publishing Network (ARPN). All rights reserved. www.arpnjournals.com THE SUITABILITY OF FLY ASH BASED GEOPOLYMER CEMENT FOR OIL WELL CEMENTING APPLICATIONS: A REVIEW Dinesh Kanesan1, Sonny Irawan1, Syahrir Ridha1, Davannendran Chandran2 and Nuriman Amsha Bin Azhar1 1Universiti Teknologi Petronas, Seri Iskandar, Perak DarulRidzuan, Malaysia 2Sunway University, Subang Jaya, Selangor, Malaysia Email: [email protected] ABSTRACT The increase in awareness towards global warming has prompted the research of alternatives to the conventional ordinary Portland Cement (OPC). In addition, studies have demonstrated that the use of geopolymer cement slurries resulted in lower carbon emission and superior cement properties compared to the ordinary Portland cement. In this study, the factors which affect the wellbore integrity in regards to cementing were identified and a comparison between Class G cement and Fly Ash Geopolymer (FAGP) cement pertaining to the identified factors were made. In addition, a thorough analysis on the factors affecting the properties of geopolymer in regards to its application in oil well cementing was performed. The results enable the finding of optimum parameters required to produce geopolymer cements for oil well applications. The FAGP cement achieved higher compressive strengths compared to Class G cement for all curing temperatures above 36oC. At optimum curing temperatures, for all curing time FAGP cement achieved higher compressive strengths in comparison Class G cement. Moreover, FAGP cement was found to be more susceptible to marine environment whereby curing medium of brine water resulted in higher compressive strengths.
    [Show full text]
  • Why Oilwells Leak: Cement Behavior and Long-Term Consequences Maurice B
    SPE 64733 Why Oilwells Leak: Cement Behavior and Long-Term Consequences Maurice B. Dusseault, SPE, Porous Media Research Institute, University of Waterloo, Waterloo, Ontario; Malcolm N. Gray, Atomic Energy of Canada Limited, Mississauga, Ontario; and Pawel A. Nawrocki, CANMET, Sudbury, Ontario Copyright 2000, Society of Petroleum Engineers Inc. To form hydraulic seals for conservation and to isolate This paper was prepared for presentation at the SPE International Oil and Gas Conference deep strata from the surface to protect the atmosphere and and Exhibition in China held in Beijing, China, 7–10 November 2000. shallow groundwater sources, casings are cemented using This paper was selected for presentation by an SPE Program Committee following review of water-cement slurries. These are pumped down the casing, information contained in an abstract submitted by the author(s). Contents of the paper, as presented, have not been reviewed by the Society of Petroleum Engineers and are subject to displacing drilling fluids from the casing-rock annulus, leav- correction by the author(s). The material, as presented, does not necessarily reflect any posi- tion of the Society of Petroleum Engineers, its officers, or members. Papers presented at SPE ing a sheath of cement to set and harden (Figure 1). Casing meetings are subject to publication review by Editorial Committees of the Society of Petroleum and rock are prepared by careful conditioning using centraliz- Engineers. Electronic reproduction, distribution, or storage of any part of this paper for com- mercial purposes without the written consent of the Society of Petroleum Engineers is prohib- ers, mudcake scrapers, and so on.
    [Show full text]
  • Well Design and Well Integrity WABAMUN AREA CO2
    Energy and Environmental Systems Group Institute for Sustainable Energy, Environment and Economy (ISEEE) Well Design and Well Integrity WABAMUN AREA CO2 SEQUESTRATION PROJECT (WASP) Author Runar Nygaard Rev. Date Description Prepared by 1 January 4, 2010 Well Design and Well Integrity Runar Nygaard Table of Contents INTRODUCTION ........................................................................................................................................... 5 BACKGROUND ............................................................................................................................................ 5 DISCUSSION ................................................................................................................................................ 5 1. WELL DESIGN AND POTENTIAL LEAKAGE PATHS ............................................................................ 5 2. EFFECT OF CO2 INJECTION ON WELL CONSTRUCTION MATERIALS ............................................ 7 2.1 Cement ............................................................................................................................................. 7 2.2 Oil Well Cements ............................................................................................................................. 8 2.3 CO2 Effect on Portland Cements ................................................................................................... 11 2.4 CO2 Corrosion on Tubulars and Steel Components .....................................................................
    [Show full text]
  • Formulation of Geopolymer Cement Using Class F Fly Ash for Oil Well Cementing Application
    International Journal of Applied Engineering Research ISSN 0973-4562 Volume 13, Number 6 (2018) pp. 3598-3604 © Research India Publications. http://www.ripublication.com Formulation of Geopolymer Cement using Class F Fly Ash for Oil Well Cementing application Dinesh Kanesan*, Sonny Irawan, Raja Rajeswary Suppiah and Tamil Alagan Kunaisekaran Universiti Teknologi PETRONAS, 32610 Seri Iskandar, Perak Darul Ridzuan, Malaysia. Abstract reactions, poor durability and leakage [2-4]. Therefore, there is a dire need to develop a sustainable cement technology which With the increasing awareness of global warming, there is a possesses superior properties compared to the OPC for oil well dire need to find a substitute for the conventional Ordinary cementing. With a reduced carbon footprint, geopolymer Portland Cement (OPC) which produces huge amounts of cement has been found to possess superior edge over OPC for carbon dioxide (CO ) during its production. Class F fly ash 2 oilwell cementing applications [2, 5-7]. However, the optimum based geopolymer cement has been identified as a potential formulation which yields superlative performance of replacement due to its abundant availability and to address geopolymer cement has to be determined. This research focuses waste management issues. The lack of research and a standard on developing a formulation for class F fly ash based formulation for geopolymer cement has hindered the efforts to geopolymer cement for the oilwell cementing applications. apply geopolymer cement for oil well cementing operations. Previous researches in the area of geopolymer cement has been focused mainly on its applications in the construction industry. FLY ASH BASED GEOPOLYMER CEMENT Therefore, there is a strong need to develop a formulation of class F fly ash based geopolymer with varying parameters, Geopolymer cement is an inorganic binder which can be ratios and compositions for oil well cementing applications.
    [Show full text]
  • Final Report Gas Flow in Wells After Cementing
    FINAL REPORT GAS FLOW IN WELLS AFTER CEMENTING Andrew K. Wojtanowicz, Wojtek Manowski, and Somei Nishikawa Louisiana State University Submitted to: US Department of Interior Minerals Management Service 381 Elden Street Herndon, Virginia 20170-4817 Baton Rouge, Louisiana September 5, 2000 i TABLE OF CONTENTS EXECUTIVE SUMMARY……………………………………………………………….. 1 1. FIELD EVIDENCE OF FLOW AFTER CEMENTING 3 1.1 Field Case Histories of Flow after Cementing 3 1.2 Field Experiments 4 1.2.1 Hydrostatic Pressure Loss Experiments 4 1.2.2 Downhole Fluid Loss Experiments 6 2. MECHANISM OF PRESSURE LOSS IN CEMENT COLUMNS 7 3. MODELING HYDROSTATIC PRESSURE LOSS IN CEMENT COLUMNS 10 3.1 Published Models 10 3.2 Cement Pressure-Unloading Model 16 3.2.1 Pressure Unloading Model Verification with Field Data 19 3.2.2 Sensitivity of Pressure Unloading Model 22 4. FIELD PRACTICES AND PROCEDURES FOR PREVENTING FLOW AFTER CEMENTING 25 4.1 Technical Requirements 25 4.2 Operator’s Procedures for Prevention of Flow after Cementing 26 5. PREDICTION OF POST-CEMENTING FLOW HAZARD 27 5.1 Risk Indicators of Flow after Cementing 27 5.2 Correlation of Risk Indicators with Field Case Histories 31 5.3 Time-to-Underbalance Method 33 5.3.1 Slurry Gellation Model 34 5.3.2 Cement Pressure-Unloading Model 37 6. CONCLUSIONS AND RECOMMENDATIONS 41 BIBLIOGRAPHY 45 APPENDIX A - FIELD CASES OF FLOW AFTER CEMENTING IN GOM 47 APPENDIX B - TECHNIQUES AND PROCEDURES TO PREVENT FLOW AFTER CEMENTING IN GOM 55 APPENDIX C - TIME-TO-UNDERBALANCE CALCULATIONS 57 ii EXECUTIVE SUMMARY The subject of this work concerns early annular flow of gas after cementing.
    [Show full text]
  • Complex Oil and Gas Well Cementing Technologies
    Complex Oil and Gas Well Cementing Technologies Science & Technology Management Department, CNPC 2015 CHINA NATIONAL PETROLEUM CORPORATION Complex Oil and Gas Well Cementing Technologies: Strengthening the foundation and body of oil and gas exploration and development! Contents 1 Introduction 3 2 Characteristic Technologies 4 3 Typical Cases 14 4 Scientific Research Equipment 20 5 Qualification Standards 21 6 Expert Team 22 China National Petroleum Corporation (CNPC) CNPC was ranked 3th among the world's largest is a state-authorized investment agency and a 50 oil companies and 4th in Fortune Global 500 in state holding company. On July 1998, with the 2014. implementation of the Institutional reform of the CNPC strictly follows by the combined strategies State Council, CNPC was reorgnized to become of increasing resource capacity, expanding market an integrated oil company of cross-regions, cross- shares and consolidating the international role, and industries and cross-countries, it adopts modern persists in regarding technical innovation as a key enterprise system to realize the integrations of framework to advance technological progress. To upstream and downstream operations, internal and develop its core businesses, focuses will be placed external trade, production and marketing. CNPC's on the solutions of key bottleneck technologies business covers six main sectors: oil and gas and key proprietary technologies. Thanks to operations, petroleum engineering service, petroleum continuously improving of the technical innovation engineering construction, petroleum equipment system, optimizing the configuration of technological manufacturing, financial services and new energy resources and strengthening the construction of development. In 2014 CNPC produced 113.67 million strong talent teams, CNPC’s technological creativity tons of crude oil and 95.46 billion cubic meters of has been considerably upgraded.
    [Show full text]
  • Development of Self-Healing Cement Slurry Through the Incorporation of Dual-Encapsulated Polyacrylamide for the Prevention of Water Ingress in Oil Well
    materials Article Development of Self-Healing Cement Slurry through the Incorporation of Dual-Encapsulated Polyacrylamide for the Prevention of Water Ingress in Oil Well G. Richhariya 1, D.T.K. Dora 1,* , K.R. Parmar 2, K.K. Pant 2, N. Singhal 3, K. Lal 4 and P.P. Kundu 5 1 Department of Petroleum & Energy Studies, DIT University, Dehradun 248009, India; [email protected] 2 Department Chemical Engineering, Indian Institute of Technology, Delhi 110016, India; [email protected] (K.R.P.); [email protected] (K.K.P.) 3 Department of Chemistry, DIT University, Dehradun, 248009, India; [email protected] 4 Institute of Drilling Technology, ONGC, Dehradun 248003, India; [email protected] 5 Department of Chemical Engineering, Indian Institute of Technology, Roorkee 247667, India; [email protected] * Correspondence: [email protected]; Tel.: +91-94387-25976 Received: 25 May 2020; Accepted: 26 June 2020; Published: 29 June 2020 Abstract: In the present work, a novel cross-linked polymer was synthesized though the anionic polymerization of cyanoacrylate with moisture as an initiator, methylene-bis-acrylamide as a cross-linker, and linseed oil as a spacer. Two layers of the synthesized polymer was coated over polyacrylamide for its homogenous impregnation in Class-G cement slurry for the synthesis of cement core. Fourier Transformation Infrared spectroscopy and X-Ray diffraction spectrum of the synthesized polymer and cement core were obtained to investigate the presence of different functional groups and phases. Moreover, the morphologies of the dual-encapsulated polyacrylamide was observed through scanning electron microscopy. Furthermore, the water-absorption capacity of the synthesized dual-encapsulated polyacrylamide in normal and saline conditions were tested.
    [Show full text]
  • A Brief Review of Gas Migration in Oilwell Cement Slurries
    energies Review A Brief Review of Gas Migration in Oilwell Cement Slurries Chengcheng Tao , Eilis Rosenbaum, Barbara G. Kutchko and Mehrdad Massoudi * National Energy Technology Laboratory (NETL), U. S. Department of Energy, 626 Cochrans Mill Road, P. O. Box 10940, Pittsburgh, PA 15236, USA; [email protected] (C.T.); [email protected] (E.R.); [email protected] (B.G.K.) * Correspondence: [email protected]; Tel.: +1-412-386-4975 Abstract: Gas migration in oil and gas wells is defined as gases and/or fluids from adjacent forma- tions invading a freshly cemented annulus. During well completions, gas and/or fluids can migrate to zones with lower pressure or even to the surface. Static gel strength (SGS), related to the yield stress of the cement, is a widely accepted measurement used to predict and minimize gas migration. In this review article, we look at the mechanisms and some possible solutions to gas migration during oil and gas well cementing. The use of static gel strength (SGS) and experimental measurements for SGS and wellbore pressure reduction are discussed. Rheological properties, including the yield stress and the viscosity of cement slurries, are also briefly discussed. Understanding the rheological properties of cement is complex since its material properties depend on cement type, as well as the shape and size distribution of cement particles. From this brief review, it is evident that in order to reduce free water and settling of the cement particles, to lower fluid loss, and to develop compressive strength in the early stages of cementing, an optimal cement slurry design is needed.
    [Show full text]
  • Comparing the Effect of Saline Water and Fresh Water on Oil Well Cementing Properties
    ISSN(Online) : 2319-8753 ISSN (Print) : 2347-6710 International Journal of Innovative Research in Science, Engineering and Technology (An ISO 3297: 2007 Certified Organization) Vol. 5, Issue 5, May 2016 Comparing the Effect of Saline Water and Fresh Water on Oil Well Cementing Properties Omotayo Adewale Omoniyi1, Kabir Anas2, Muhammad K.Abba3 Senior Lecturer, Department of Petroleum Engineering, Abubakar Tafawa Balewa University Bauchi, Bauchi State, Nigeria1 Undergraduate Student, Department of Petroleum Engineering, Abubakar Tafawa Balewa University Bauchi, Bauchi State, Nigeria2 Assistant Lecturer, Department of Petroleum Engineering, Abubakar Tafawa Balewa University Bauchi, Bauchi State, Nigeria3 ABSTRACT: The success of oil field cementing operations, whether for completion or for remedial purposes, is a vital factor in determining the well’s future productive life and eventually return on the well owner’s investment. The general purposes for any well cementing job are zonal isolation and segregation, corrosion control, formation stability and pipe strength improvement, and to fully achieve these purposes, specialised cement formulations with critical solid-to-water ratios, slurry density and other cement properties must be closely controlled. The most significant effect on cement performance is caused by the presence of sodium chloride in sea water. With increased offshore drilling activities and also in some instances due to difficulty and expense in bringing fresh water to the job, the use of sea water for mixing cement slurries for down-hole cementing applications has increased significantly. Also in locations where the wellbore extends through a salt dome, large amounts of sodium chloride are sometimes added to the mixing water to minimise the action of the cement slurry dissolving salt from the formation.
    [Show full text]